Semiconductor contact structure having stress buffer layer formed between under bump metal layer and copper pillar

Plain English Translation

A semiconductor apparatus includes a copper pillar and a stress buffer layer, where the cross-sectional area of the copper pillar is at least as large as that of the stress buffer layer. The apparatus addresses challenges in semiconductor packaging, particularly in ensuring reliable electrical and mechanical connections between components. The copper pillar serves as a conductive interconnect, while the stress buffer layer mitigates stress and prevents damage during thermal cycling or mechanical stress. By ensuring the copper pillar's cross-sectional area is equal to or larger than the stress buffer layer's, the design maintains structural integrity and electrical performance. This configuration is particularly useful in advanced packaging technologies, such as flip-chip or 3D integration, where thermal and mechanical stresses can degrade connections. The stress buffer layer, typically made of a compliant material, absorbs stress while the copper pillar provides robust conductivity. The invention improves reliability and longevity of semiconductor devices by balancing mechanical resilience and electrical efficiency.